<html>

<head>
<title>Learning WebGL &mdash; lesson 1</title>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">

<script type="text/javascript" src="glMatrix-0.9.5.min.js"></script>
<script type="text/javascript" src="webgl-utils.js"></script>

<script id="shader-fs" type="x-shader/x-fragment">
    #ifdef GL_ES
    precision highp float;
    #endif

    void main(void) {
        gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
    }
</script>

<script id="shader-vs" type="x-shader/x-vertex">
    attribute vec3 aVertexPosition;

    uniform mat4 uMVMatrix;
    uniform mat4 uPMatrix;

    void main(void) {
        gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
    }
</script>


<script type="text/javascript">

    var gl;
    function initGL(canvas) {
        try {
            gl = canvas.getContext("experimental-webgl");
            gl.viewportWidth = canvas.width;
            gl.viewportHeight = canvas.height;
        } catch (e) {
        }
        if (!gl) {
            alert("Could not initialise WebGL, sorry :-(");
        }
    }


    function getShader(gl, id) {
        var shaderScript = document.getElementById(id);
        if (!shaderScript) {
            return null;
        }

        var str = "";
        var k = shaderScript.firstChild;
        while (k) {
            if (k.nodeType == 3) {
                str += k.textContent;
            }
            k = k.nextSibling;
        }

        var shader;
        if (shaderScript.type == "x-shader/x-fragment") {
            shader = gl.createShader(gl.FRAGMENT_SHADER);
        } else if (shaderScript.type == "x-shader/x-vertex") {
            shader = gl.createShader(gl.VERTEX_SHADER);
        } else {
            return null;
        }

        gl.shaderSource(shader, str);
        gl.compileShader(shader);

        if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
            alert(gl.getShaderInfoLog(shader));
            return null;
        }

        return shader;
    }


    var shaderProgram;

    function initShaders() {
        var fragmentShader = getShader(gl, "shader-fs");
        var vertexShader = getShader(gl, "shader-vs");

        shaderProgram = gl.createProgram();
        gl.attachShader(shaderProgram, vertexShader);
        gl.attachShader(shaderProgram, fragmentShader);
        gl.linkProgram(shaderProgram);

        if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
            alert("Could not initialise shaders");
        }

        gl.useProgram(shaderProgram);

        shaderProgram.vertexPositionAttribute = gl.getAttribLocation(shaderProgram, "aVertexPosition");
        gl.enableVertexAttribArray(shaderProgram.vertexPositionAttribute);

        shaderProgram.pMatrixUniform = gl.getUniformLocation(shaderProgram, "uPMatrix");
        shaderProgram.mvMatrixUniform = gl.getUniformLocation(shaderProgram, "uMVMatrix");
    }


    var mvMatrix = mat4.create();
    var pMatrix = mat4.create();

    function setMatrixUniforms() {
        gl.uniformMatrix4fv(shaderProgram.pMatrixUniform, false, pMatrix);
        gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform, false, mvMatrix);
    }



    var triangleVertexPositionBuffer;
    var squareVertexPositionBuffer;

    function initBuffers() {
        triangleVertexPositionBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, triangleVertexPositionBuffer);
        var vertices = [
             0.0,  1.0,  0.0,
            -1.0, -1.0,  0.0,
             1.0, -1.0,  0.0
        ];
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
        triangleVertexPositionBuffer.itemSize = 3;
        triangleVertexPositionBuffer.numItems = 3;

        squareVertexPositionBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, squareVertexPositionBuffer);
        vertices = [
             1.0,  1.0,  0.0,
            -1.0,  1.0,  0.0,
             1.0, -1.0,  0.0,
            -1.0, -1.0,  0.0
        ];
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
        squareVertexPositionBuffer.itemSize = 3;
        squareVertexPositionBuffer.numItems = 4;
    }





	var currentlyPressedKeys = {};

    function handleKeyDown(event) {
        currentlyPressedKeys[event.keyCode] = true;
    }


    function handleKeyUp(event) {
        currentlyPressedKeys[event.keyCode] = false;
    }

	var pitch = 0;
    var pitchRate = 0;

    var yaw = 0;
    var yawRate = 0;

	var roll = 0;
	var rollRate=0;

    var xaw=0;
    var xawRate=0;

    var xPos = 0;
    var yPos = 0.4;
    var zPos = 0;

    var speed = 0;

function handleKeys() {
		/*IZQUIERDA - DERECHA*/
		if (currentlyPressedKeys[87]) {
            // KEY W
            speed = 0.003;
        } else if (currentlyPressedKeys[83]) {
           // KEY S
           speed = -0.003;
        } else {
            speed = 0;
        }
        if (currentlyPressedKeys[37] ) {
            // Left cursor
            yawRate = 0.05;
            rollRate=-10;
        } else if (currentlyPressedKeys[39]) {
            // Right cursor
            yawRate = -0.05;
            rollRate=10;
        } else {
            yawRate = 0;
            rollRate=0;
        }

        if (currentlyPressedKeys[38] ) {
        	// Up cursor
            xawRate = -0.1;
        } else if (currentlyPressedKeys[40]) {
            // Down cursor
            xawRate = 0.1;
        } else {
            xawRate = 0;
        }

    }


    var lastTime = 0;
    // Used to make us "jog" up and down as we move forward.
    var joggingAngle = 0;

     function degToRad(degrees) {
        return degrees * Math.PI / 180;
    }


    function animate() {
        var timeNow = new Date().getTime();
        if (lastTime != 0) {
            var elapsed = timeNow - lastTime;

            if (speed != 0) {
                xPos -= Math.sin(degToRad(yaw)) * speed * elapsed;
                zPos -= Math.cos(degToRad(yaw)) * speed * elapsed;

				yPos -= 20 * speed;

            }

            	xPos -= Math.sin(degToRad(yaw)) * 0.001 * elapsed;
                zPos -= Math.cos(degToRad(yaw)) * 0.001  * elapsed;
            	zPos -= 0.001 * elapsed;
				yPos -= 0.001 * elapsed;

			roll=rollRate;

            yaw += yawRate * elapsed;
            xaw +=xawRate  * elapsed;
            pitch += pitchRate * elapsed;

        }
        lastTime = timeNow;
    }



	function tick() {
        requestAnimFrame(tick);
        handleKeys();
        drawScene();
        animate();
    }
 function drawScene() {

        gl.viewport(0, 0, gl.viewportWidth, gl.viewportHeight);
        gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

        mat4.perspective(45, gl.viewportWidth / gl.viewportHeight, 0.1, 100.0, pMatrix);

        mat4.identity(mvMatrix);

       // mat4.rotate(mvMatrix, degToRad(-pitch), [1, 0, 0]);
        mat4.rotate(mvMatrix, degToRad(-xaw), [1, 0, 0]);
        mat4.rotate(mvMatrix, degToRad(-yaw), [0, 1, 0]);
        mat4.rotate(mvMatrix, degToRad(roll), [0, 0, 1]);
        mat4.translate(mvMatrix, [-xPos, -yPos, -zPos]);



 		mat4.translate(mvMatrix, [-1.5, 0.0, -17.0]);
        gl.bindBuffer(gl.ARRAY_BUFFER, triangleVertexPositionBuffer);
        gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, triangleVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);
        setMatrixUniforms();
        gl.drawArrays(gl.TRIANGLES, 0, triangleVertexPositionBuffer.numItems);

		mat4.translate(mvMatrix, [0.0, -7.0,0.0]);
        gl.bindBuffer(gl.ARRAY_BUFFER, triangleVertexPositionBuffer);
        gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, triangleVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);
        setMatrixUniforms();
        gl.drawArrays(gl.TRIANGLES, 0, triangleVertexPositionBuffer.numItems);

        mat4.translate(mvMatrix, [3.0, 0.0, 0.0]);
        gl.bindBuffer(gl.ARRAY_BUFFER, squareVertexPositionBuffer);
        gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, squareVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);
        setMatrixUniforms();
        gl.drawArrays(gl.TRIANGLE_STRIP, 0, squareVertexPositionBuffer.numItems);
		}

    function webGLStart() {
        var canvas = document.getElementById("lesson01-canvas");
        initGL(canvas);
        initShaders();
        initBuffers();

        gl.clearColor(0.0, 0.0, 0.0, 1.0);
        gl.enable(gl.DEPTH_TEST);
		document.onkeydown = handleKeyDown;
        document.onkeyup = handleKeyUp;

        tick();
    }


</script>

</head>


<body onload="webGLStart();">
    <canvas id="lesson01-canvas" style="border: none;" width="500" height="500"></canvas>
</body>
</html>
